// 实现一个 sleep 函数 比如 sleep(1000) 意味着等待1000毫秒，可从 Promise、Generator、Async/Await 等角度实现
// 1、从promise
function sleep(delay){
  return new Promise((resolve,reject)=>{
    setTimeout(()=>{
      resolve()
    },delay)
  })
}
sleep(1000).then(console.log(1))

// 2、async
function sleep(delay){
    return new Promise(resolve=>{
      setTimeout(resolve,delay)
    })
    async function output(){
      const out=await sleep(1000)
      console.log(1);
      return out
    }
    output()
  }
 